Chain tongs



M. DUNCAN CHAIN TONGS March 3, 1931.

Filed May 9] 1929 Mylar fill/20a);

W abtomq i thesame and a larger amount of energy; must l a'tented Mar.3, 19 31 U ED STATES PATENT we MYLER DUNCAN, or ALLIANCE, onio CHAIN moes Application filed May 9,

In the past, numerous wrenches of this class have been devised in whichachain en circles the pipe and is connected with a leverage system whichis operated by a lever for turning the pipe. Some of the priorconstructions have also included a jaw member as part of theleveragesystem, which conta'ctswith the pipe at a point adjacent theoperating lever, thejawmember usually being provided with teeth or aserrated surface for biting into the pipe. In such old constructions,where great forces are necessary to be applied for twisting the pipe,the jaw member often crushes the pipe inward because'of the applicationof great force, since such application of force only tends toti'ghten'the chain-around the pipe and draw the jaw inward into thepipe. Thus chain tongs of this characte'rare not useful for the purposefor which they are.

designed because they'cause a destruction of the pipe in use rather thana turning thereof. Moreover, it'is' very diificult to back oft'chaintongs now in common use for taking anew bite because: a release ofthe operating lever does not suflicient'ly loosen the chain from-"aroundthe circumference of the pipe to permit the chain and jawto be adjustedat a new position, without the necessity of entirely releasing the chaintong from the pipe, repositioning theisame and again hookcommonconstruction are transmitted at the. places where thechain tong vjawteeth cons tact or bite into the pipe.

there is an unequal distribution of work" Accordingly,

around the periphery ofthe-pipe in twisting be expended than isnecessaryfor twisting the pipebecause of the limited force trans- 1929.. serialNo. 361,663.

mitting connection'betweenthe chain tong and the'pipe. I

An object of my invention is therefore to provide a chaintong in whichthe difiiculties encountered in using chain tongs of common constructionare obviated; and more particularly, in which the chain tong has a forcetransmitting connection with the pipe substantially throughout theentire circumferenceof the chain tong with the pipe; in which 69 I thechain tong is being applied for twisting a pipe-willnot cause the'pipeto become crushed; in which the chain tongin being used may be quicklyand easily backed off for taking'aanew bite; and in which the design" 1by a construction hereinafter set forth inde tail, which may be statedin general terms as including a jaw having pivoted portions providedwith 'arcuate serrated or toothed faces for contact with the pipe, anoperating lever connected with the jaw, a link chain connected at oneend with the 'operatinglever, each link being provided with arcuateserrated or toothed facesfor contact with the pipe,and means beingprovided fordetachably connecting'any of the links at the other 8 endportion of the chain with the jaw.

A preferred embodiment of my invention is illustrated in theaccompanying drawings, in which Figure l is a plan viewof the newimproved chain tong, the same being shown in full lines in operativeposition around a pipe or well casing, and the same being shown indotdashxlines in the position which the various parts assume when I thechain tong is just.

about'tobe backed off to/take a new bite; Fig.2 is a section as on theline 22, Fig. 1; and i jaw'sections. I

Similar numerals refer to similar part-s throughout the drawings. Thechaintong may consist of the operat-'- ig. 3 is a perspective .view ofthe pivoted ing-handle a, which is pivotally mounted as yjo at 5, to oneportion 6, of the jaw 7 by means of thebolt 8.

At one portion 6, of the jaw 7, there may be provided a slot 9 alongwhich the operating handle 4 extends, and the pivot bolt 5 is pivoted tothe jaw portion 6 as by the holes 10 provided in the jaw sectionat theplace. of the slot .19. I

The jaw 7 also consists of a second jaw portion 11, which is pivoted asat 12 to the first jaw portion 6, the pivotal movementrof the jawportions 6 and 11 with respect to each other being limited by thecoaction of the-bifurcated portions 11a and the shoulders 6a,; and eachjaw portion 6 and "I1 is provided Witlranarcuate serrated'or toothedface 13. The jaw portion 11 may also beprovided on a ,portionoppositethe serrated face 13, with a slot li extending betweenoutwardlyprojecting ribs 15 having a tooth .or hook contour-asshownat l6,fora-purpose which will behereinafter described.

The .chain tong also consists of the chain indicated generally at 17,which may be'piv- Otally. connectedat one end .18, to theoperatingrha'ndle 4, by-thelinks 19,-which are pivoted to :the operatinghandle as at 20.

The chain. 17 consistsof links 21, 22 and 23, I

pivotally connected ,to each .other as. at 2d,

andeachof the links 21,22 and 23isprovided with an arcuateserrated ortoothed face 25..

It is pointed .out that the .ar cuate face 13 of the jaw portions, andthe arcuate faces 25 of the chain links all have substantially the samecurvature.

The links 21, .22 and 23. at the endof the chain 17 which is notconnected to the operating handle, may be pivotally connected togetheras by means of pins 26, which-extend outward a substantial distance from@the outer facesof'the .links 22, and 23, asshown at 27 in Fig.2. 7 V VV Asshownin Fig.2, the slot 14 in theouter surface of the jaw portion11, has a width substantially equal :to the width or thickness of thelink chain 17, so that the link chain maybe slidable in the slot, inorder to re leasablyXengage-the outwardly extending portions 27 of thepins 26, with the hooks or .;teeth 16 provided inthegribs 15. i

In usingthe chain-tong for screwing up a pipe or tubelsuch as shown at28, the link chain 17 is placed around and encircles the periphery ofthe :pipe,:the' jaw .portionsareiengaged against the periphery of the:pipe,.-and the pivot .pin ends .27 are engaged by the hooks .orteet h16:0f the .jaw portion 11. ,The operating handle is then operated in thedirection shown :by :the :arrow .in Fig. l ofathe drawings which causesthe chain-and aw:to tighten around the periphenyof the pipe and becauseof the substantially continuousarcuate toothed contact between the. j awand link chainand the pipe, the pipe will be. rotated or screwed in thedirection shown by the arrow in Fig. 1.

lVhen it is desired to take a new bite for further twisting or turningthe pipe, the operating handle is merely rotated in the reversedirection at which time the parts assume the position shown in dot-dash,lines in .Fig. 1

wh-enthe chainand jaw portions maybe reversely slipped around the pipeuntil the desired new bite posltlon has been reached,

;wh-en theoperating handle will be again rotated in the direction shownby the arrow in Fig. 1 for further twisting or turning the ripconnectionsbetween the linksand between the portions the jaw, the chaintong, within certain limits may be used in connection with pipes ofvarying diameters, in each case there being contact between the chaingong and 1i. iesnbstantiall .throu hout'the eri her l .r b ,P yv

ofthe pipe. v

Accordingly there is an equal 7 distribution of the turning 01 twistingforces applied to the pipe throughout the entire circumference of thepipe, and the-chain .tong'thus will not-cause the pipe to becomecrushed.

.hioreovenas is evident from an inspection ofthe:drawings,-the-chaintong may be read ily andeasily backedjoff for taking-a new bite rwithout the, necessity of releasing the chain tong from the pipe,repositioning the same and again hooking the chain-up. I And finally,athe-design of the varlous parts is extremely simple In construction,strong and durablacheapto manufacture, and .efiec- I tive in operation;:and theitool may be quickly and readily used for the purpose for whichit is designed.

I claim: r

l. A chain tong comprising a jaw including apa-ir of pivotedportions,.an operating handle pivoted to one portion, a link chainconnectedat one endito the operating handle, means detachably connectinganother 'portion of the chain withthe' other j aw portion for encirclinga pipe, and means limiting the pivotal movement of the jaw portions;

2. A chain tong comprising a jaw :including a pairof pivoted portions,an operating handle pivoted to oneportion, a link chain connected at oneend to the operating hanof at 20 as dle, means detachably connectinganother portion of the chain with the other jaw portion for encircling apipe, means limiting the pivotal movement of the jaw' portions, and 5the jaw portions and chain links each having an arcuate toothed faceconforming substantially with the curvature of the'pipe encircled. V

3. A chain tong comprising a jaw includ- V m ing a pair of pivotedportions, an operating handle pivoted to one portion, a link chainconnected at one end to the operating handle, means detachablyconnecting another portion of the chain with the other jaw portion for 5encircling a pipe, means limiting the pivotal movement of the'j awportions, and the jaw portions and chain links each having an arouatetoothed face conforming substantially with the curvature ofthe pipeencircled, said 20 arcuate toothed faces of the jaw and links contactingwith substantially the entireperiphery of the pipe when encircled.

- In testimony thatI claim the above, I have hereunto subscribed myname. 25 MYLEltDUNCAN.

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